The present invention relates to new substituted N-phenylaminopyrazoles and to hair dye compositions containing these compounds and to a process for dyeing hair.
It is already known to use leuco derivatives of indoaniline for dyeing hair. These colorless compounds are applied to the fibers to be dyed in aqueous solution and oxidized by air or some other oxidant to form indoanilines which are colored compounds. Due to the good solubility of leuco compounds the dyes obtained in this way have intensity and fastness properties which are superior to those of dyeing obtained by direct application of indoanilines. For example, German Patent applicatons DE-OS 22 34 525 and DE-OS 22 34 476 describe leuco derivatives of these compounds. However, the dyeing intensities which can be achieved with these leuco derivatives are unsatisfactory.